Switching to less processed foods does not guarantee a healthy diet; the type of food may be more important than the level of processing.
Processed foods get a lot of negative attention, but when it comes to nutrition, that bad reputation isn’t entirely justified.
In a recent study, researchers compared two diets: one emphasizing minimally processed foods and the other emphasizing ultra-processed foods. They found that switching to “simpler” foods—meaning less processed—doesn’t necessarily guarantee a healthy diet. This suggests that the specific types of foods we consume may be more important than their level of processing.
“This study shows that it is possible to eat a low-quality diet even when choosing mostly minimally processed foods,” Julie Hess, a doctoral student and research nutritionist at the USDA-ARS Grand Forks Human Nutrition Research Center who led the study, said in a press release.
“It also suggests that more processed and less processed diets may not be equally nutritious or nutritious, but the more processed diet may have a longer shelf life and cost less,” he continued.
What are processed foods??
Processed food refers to the extent of physical, biological, or chemical changes a food undergoes before it is consumed. Minimal processing includes cleaning, cutting, grinding, drying, fermentation, or pasteurization, as seen in foods such as cut or frozen vegetables and packaged nuts, grains, and cereals.
On the other hand, highly processed foods involve significant transformations, such as hydrogenating oils, modifying starches, adding flavor enhancers or coloring agents. Examples include canned or prepared soups and sauces, soft drinks, flavored yogurt and margarine.
Researchers from the USDA-ARS Grand Forks Human Nutrition Research Center, the Soybean Nutrition Institute Global, and the Universities of Minnesota and North Dakota questioned the idea that increasing consumption of minimally processed foods automatically improves diet quality.
This follows previous findings showing that it is possible to create a nutritious menu while adhering to dietary guidelines, even when most of the calories come from foods classified as ultra-processed, according to the NOVA scale, which categorizes foods by their level of processing.
To find out, they modified a predetermined menu for the typical Western diet, which included calorie-dense and nutrient-poor foods (such as refined grains, red meat, high-sugar foods and drinks, and high-fat dairy products). They then created a similar menu that replaced highly processed foods with simpler, minimally processed options whenever possible.
The less-processed menu had 20% of its calories from minimally processed foods and the remaining 67% from ultra-processed foods; however, specific food details were not available at the time of publication.
The team then compared the nutrient content and index scores of both menus, as well as assessed the cost and shelf life of the included foods to assess nutritional and socioeconomic outcomes.
Low or high processing, same malnutrition
When it comes to nutritional value, the two diets received a Healthy Eating Index score of 44 and 43 out of 100, respectively. This is a relatively low score that reflects poor adherence to the Dietary Guidelines for Americans, according to the press release.
The less processed menu was also more than twice as expensive, costing $34.87 per person per day, compared to $13.53 for the ultra-processed menu. The shelf life of minimally processed food was also shorter, with a median expiration time of 35 days, compared to 120 days for more processed options.
“This study shows that it is possible to eat a poor-quality diet even when you choose mostly minimally processed foods,” Hess commented.
Replacing processed foods with less processed options won’t automatically improve nutrition. In fact, a previous study by Hess and colleagues showed that it’s possible to have a high-quality menu that meets dietary guidelines even when most of the calories come from highly processed foods.
The study advises against rejecting processed foods based solely on buzzwords, as this approach can negatively impact both your budget and your diet. “The results of this study suggest that creating a nutritious diet involves more than just considering food processing as defined by NOVA,” Hess said.
For consumers, this means a healthy diet requires considering the types and nutritional values of foods, rather than focusing on unnecessary levels of processing.
Reference: Julia Hess et al., Unprocessed, but SAD: A Standard American Diet Made with Less Processed Foods Is Still a Standard American Diet. Abstract presented at NUTRITION 2024, held in Chicago, IL, USA, from June 29 to July 2, 2024.
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